Arkansas State University 
Department of Chemistry
and Physics
CHEM1013
Exam 5
(Note: only the questions are listed, spaces have been removed for brevity)

SHOW WORK ON ALL PROBLEMS

1. Using the table provided, calculate the enthalpy change from the bond energies. (15 points)

  2 H2  +   O2  --------->   2 H2O

2. Define each of the follwoing as either an open, closed or isolated system.    (6 points)

 a) An unopened egg warming on the counter ________________

 b) A warm cup of coffee cooling on the table ________________

 c) A closed thermos of hot chicken noodle soup _________________

3. Define Hess’ Law.      (5 pts)

4. Using the table provided, calculate the heat of reaction for:       (10 points)

 2 C2H2 (g)  +   5 O2 (g)  -------->  4 CO2 (g)  +   2 H2O  (l)





5. Given the following reactions, calculate the enthalpy change for the formation of C2H6 from its elements.  (15 points)

C(graphite)  +  O2 (g) --------->  CO2 (g)        DH = -393.5 kJ

 H2 (g)   +  1/2 O2 (g) --------->  H2O (l)       DH = -285.8 kJ

 2 C2H6 (g)  +  7 O2 (g) -------->  4 CO2 (g) + 6 H2O (l)DH = -3119.6 kJ
___________________________________________________________________

  2 C(graphite)  +  3 H2 (g) ----->  C2H6 (g)

6. Fill in the blank.     (2 points each)

a ) combination of an alcohol and an organic acid___________________

b) class of sweet-smelling organic compounds _______________

c) class of compounds which includes the compound which gives bananas their distinctive odor ____________________

d) vinegar belongs to which class of compounds _________________

e) glycine belongs to which class of compounds _________________

f) compounds which contain only carbon and hydrogen _____________________

g) formula for methane ___________________

h) acetone belongs to which class of compounds ______________________

i) organic chemistry is the chemistry of which element _________________

j) formaldehyde is used as a ___________________________

k) gasoline belongs to which class of compounds _____________________

l) used as a refridgerant, destroys the ozone layer _____________________

m) common name for isopropyl alcohol ___________________________

n) class of compounds commonly used as fuels ___________________________

7.  Identify the class of organic compounds that best fits the structures shown below.  Place the answer on the line below the compound.   (3 points each)
 
 
Hint: Right click on the image for the answer (after view image - the compound type is the name of the file, i.e. the image name for compound g is ester.jpg.  Compound g is an ester)